This invention relates in general to printers utilizing a ribbon cassette for feeding an ink ribbon to the print head of the printer and in particular to a new and improved cassette for a printer which is particularly useful in point-of-sale transaction terminals utilizing a wire matrix type printer which traverses a plurality of print stations, although could be useful in any printer in which the print head traverses a record media for printing alphanumeric characters thereon.
While it is recognized that there are a number of ribbon cassettes for supplying inked ribbon to a print head in alphanumeric printers, such as typewriters, manual or automatic, and other types of printers, such as those used on point-of-sale terminals, one of the undesirable features of existing cassettes is the manner in which they cooperate with some type of mechanism which is coordinated with the print head for feeding the inked ribbon to the print head during use. The most common means is a set of gears on the printer which will engage or intermesh with a gear on the cassette so as to actuate the ribbon feed mechanism as the print head traverses the record media. So far as it is known, all existing cassettes have a positive intermeshing or interengaging direct contact relationship with a similar and corresponding mechanism on the printer itself. Such a direct contact relationship requires precise positioning of the cassette relative to its corresponding interengaging or intermeshing mechanism and if the positioning is not precise, it is often the cause of malfunction. That is to say, misalignment may cause a malfunction.
It is a first object of this invention, therefore, to provide a cassette which will cooperate with the print head of a printer in such a manner that the installation of the cassette on the printer does not require a precise relationship to the printer to function satisfactorily.
While it is also recognized in the prior art cassettes that a mobius loop has been used and that some prior art cassettes have been provided with means for inking the ribbon as it passes through the cassette, while still others have utilized the concept of a randomly packed endless ribbon, none of the prior art cassettes have recognized the advantage of providing a means of inking an endless mobius loop as the ribbon first enters the cassette and before it is randomly packed therein so that the ink can sufficiently migrate through the threads of the ribbon and at the same time afterwards be held in randomly packed inked condition ready for egress from the cassette. The advantage of this arrangement is, of course, a provision of an extremely long life to the ribbon, plus a ribbon that is well inked when it is before the print head.
Accordingly, it is still another object of this invention to provide a cassette with a means of inking a mobius loop ribbon as it passes through the cassette such that the ribbon has sufficient time when in engagement with inking means to have a good exchange of ink from the inking means to the ribbon.
Another object of this invention is to provide a simple, inexpensive ribbon cassette with a mobius loop ribbon which can supply a print head of a printer with a sufficiently inked ribbon over a long period of time.
Finally, still another object of this invention is the provision of a new and improved pulley in a printer for guiding the ink ribbon to and from the cassette, thus preventing malfunction of the ribbon and print head.